I know this is a beginnger question, so I apologize in advance.
I'm a tech teacher in K-12. There have been times when I called tech support and the tech has come and run some sort of diagnostic on a laptop I was having trouble with. Several times, they've concluded the diagnostic and said, "the hard drive is bad, it has to be replaced". My question is, what did they do and how do I do it? I've looked for the answer on the web and I can't find it. I learned about "error checking" but I don't think that was it. I vaguely remember it being run before windows actually started up. Any help would be appreciated.